<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>弹窗</title>
</head>
<body>
    <button onclick="alert('是否确定！')">alert</button><br/>
    <button onclick="confirm('是否确定！')">confirm</button><br/>
    <button onclick="prompt('输入内容')">prompt</button><br/>
</body>
</html>